Question

Assume that you have a machine as shown in section 3.2.2 of Block 3 having the micro-operations as given in Figure 10 on page 62 of Block 3. Consider that R1 and R2 both are 8 bit registers and contains 11010011 and 10000111 respectively. What will be the values of select inputs, carry-in input and result of operation (including carry out bit) if the following micro-operations are performed? (For each micro-operation you may assume the initial value of R1 and R2 as given above)
(i) Subtract with borrow R2 from R1
(ii) Exclusive OR of R1 and R2
(iii) Shift left R1 twice
(iv) Increment R1

Answer 1

(i) Subtract with borrow R2 from R1
(ii) Exclusive OR of R1 and R2
(iii) Shift left R1 twice
(iv) Increment R1